Title: A low cost and portable single finger assistive device using air muscles

Authors: Thomas Hurst, K.C. Aw

Addresses: Mechanical Engineering, The University of Auckland, 20, Symonds Street, Auckland, New Zealand. ' Mechanical Engineering, The University of Auckland, 20, Symonds Street, Auckland, New Zealand

Abstract: The paper shows the development of a low cost, lightweight and portable device to assist index finger movement for people with limited or no ability to use their hands. The mechanical system consists of a pair of air muscles connected to braided polymer cables applying force to the finger. The distal joints are actuated simultaneously by a single air muscle and rotational lever system while a second air muscle acts on the metacarpophalangeal (MCP) joints joint with a minor positive effect on the distal joints. The distal interphalangeal (DIP) and MCP joints are capable of achieving rotations up to 40° from resting and the proximal interphalangeal joint up to 65°. The device is capable of producing forces over 1 kg for a single finger. Force from the muscle itself increasing up to 3 kg at maximum contraction, producing a strong compliant force. Finger movement is similar to the curling motion of the human finger and can quickly and firmly grasp medium sized objects such as a plastic bottle of water.

Keywords: air muscles; wearable assistive devices; single finger assistive devices; index finger movement; index fingers; hand disability; rotational levers; curling motion; grasping; finger forces.

DOI: 10.1504/IJBBR.2011.040033

International Journal of Biomechatronics and Biomedical Robotics, 2011 Vol.1 No.3, pp.149 - 159

Published online: 12 May 2011 *

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